Room temperature cured solid propellant



Ice 3,399,088

Patented Aug. 27, 1968 over a predetermined period of time. The ingredients are zfiidded to a suitable mixer so that the liquids are added rst, the solids are added next and the catalyst is added 1 SOLID PROPELLANT 1 Charles M..Christian and Robert B. Kruse, Huntsville, 5 Thus at room temperature (approxlmately 77 Ala., assignors to Thiokol Chemical Corporation, Bris- 5 .egrees polymer hydroxyl terminated polybuta to], P3. a corpomfimof Delaware V dlene (HTPB) 1s added to the mixer, then the cure agent No Drawing. Filed Apr. 21, 1966, Ser. No. 544,080 toluene dllsocyanate is added, a Second P y 2 Claims. (Cl. 149-19) epoxidized novolac resin (EN) is heated sufiiciently so that it will flow freely and then it is added to the mixer. Novolac resins are produced by the reaction of phenol and formaldehyde in acid solution. Such resins have the following structure:

3,399,088 ROOM TEMPERATURE CURED ABSTRACT OF THE DISCLOSURE A room temperature cured propellant composition consisting in parts by weight of a hydroxyl terminated polybutadiene polymer, toluene diisocyanate, epoxidized 0H 0H 11 11 novolac resin, 2-ethyl hexoic acid salt of tri(dimethyl 15 amino methyl) phenol, butyl carbitol formal or butyl ferrocene, ammonium perchlorate and powdered aluminum. CH

This invention relates to improvements in composite solid propellants and more particularly it relates to composite solid propellants that may be cured at room temperature. lation of a novolac type base resin. The resulting resins One of the valuable properties of propellant composihave multi-epoxy functionality with the following structions is their ability to transform readily from a liquid ture:

Novalac resin Epoxy novolac resins are accomplished by the epoxy- C... L stem J or semi-liquid state to a tough elastomeric solid. This The unground oxidizer ammonium perchlorate (AP) change is accomplished by the addition of a chemically is then added and next a plasticizer butyl carbitol formal active reagent known as a curing agent, activator or or butyl ferrocene, then triphenylphosphite may be added catalyst. Some curing agents promote curing by catalytic as a cure accelerator and next the ground oxidizer amaction, others participate directly in the reaction and are monium perchlorate (AP) followed by powdered alumiabsorbed into the polymeric chain. Depending upon the num (Al), as the solids are added the ingredients are particular agent, curing may be accomplished at room thoroughly agitated or mixed to be sure the solids have a temperature, with heat provided by exothermic reaction complete wetting by the liquids. Finally the cure catalyst or by application of external heat. 2-ethylhexoic acid salt of tri(dimethyl amino methyl) It is an object of this invention, therefore, to provide phenol is added and after a thorough mixing the ingrea solid propellant that can be cast mixed and polymerized dients are cast into a motor case and permitted to stand at room temperature. at room temperature for the required curing time which It has been found that curing solid propellants at elemay continue from 24 to 120 hours. vated temperatures introduces hazards, because of the The following examples are typical of the mixes that oxidizer that is incorporated in the solid propellant. If produce a room temperature cured solid propellant as the oxidizer is too sensitive or thermally unstable, shocks in the instant invention: transferred to the solid propellant may cause premature Polymer 14.0 9.8 11.5 8.1 10.0 10.3 10.3 combustion or other irreparable damage to the solid Cum agent 1.5 L1 L1 0.8 L0 M 0.7 propellant. Polymerresin. 5.0 4.7 5.7 4.0 1.7 1.7 1.7 It is another Object of the invention, therefore, to P llititiillff:::::::::::::::: 2:2 8:3 2:3 3:3 31% 8:3 2:3 vide a solid propellant that will eliminate the hazards Oxidzer: d 13 0 1 6 14 3 170 7 0 17 0 7 0 roun a that are associated with solid propellants that are cured Ungmund 5L0 54.4 5L6 5L0 5L0 5L0 5L0 at elevated temperatures. Aluminum 11.5 16.0 11.5 16.0 16.0 16.0 16.0

Other problems that are solved by the use of room temperature cured solid propellants arethe lowering of manufacturing costs and the reduction of residual propellant stresses that are normally associated with high temperature cured propellants, as well as extending the strain 6 capacity of the propellant over the present high temperature cured propellants and also extending the temperature The cure rate for the solid propellant can be altered by the ratio of the curing catalyst that is used, as set forth in the foregoing examples, also physical and thermal properties of the solid propellant can be altered by the size of the ground and unground oxidizer.

Various modifications and alterations of this invention will become apparent to those skilled in the art without environmental storage capabllltles of rocket motors. departing fr the scope and Spirit f this invention; and

Preparation of the room 'tempel'ature cured Solid P it is to be understood that the foregoing description merepellant is accomplished by simply a roughly admi 1y represents embodiments thereof which do not unduly ing the ingredients and permitting curing to take place limit the invention.

What is claimed isr V 4 2-, A un pp lan om qsi p i file m i 11 A'ro'om"temperature'cured profillafifeompo'sition" butyl ferrob rie is'Su1fituted for butyl'eairbitol formal. consisting in parts by weight of 8.1 to 14 parts of a hydroxyl terminated polybutadiene polymer, 0.7 to 1.5 parts References Clted of toluene diisocyanate, 1.7 to 5.7 parts of an epoxidized 5 UNITED ATENTS novolac resin, 0.2 to 0.5 parts of Z-ethyl hexoie acid salt 3,109,761 -11/ 1963 .Cobb et a1, 149 19 of tri (dimethyl amino y phenol, 00 to 4 p s of 3,249,475 5/1966 Jorczak et-ial. 149 19 butyl carbitol formal, 64.0 to 68.0 parts of ground and 3 257,248- 6/1966 Sh t-a 1,

unground ammonium perchlorate, and 11.5 to 16 parts of powdered aluminum.

10 REuBE EPsTEm rim Examiner 7 

